WASHINGTON -- The Federal Reserve has published its rule on the maximum fee that banks may charge retailers for processing debit-card transactions. The rule, which will take effect on Oct. 1, sets the fee cap at 21¢.

The Federal Reserve was given the job of overseeing card fees under the Durbin Amendment to last year's Dodd-Frank Wall Street Reform and Consumer Protection Act. Retailers generally favor it, as it will reduce their transaction costs. The Merchants Payments Coalition was formed to support the cap.

Banks have opposed it, contending that capping card fees will compel them to recover the lost revenue by shifting costs to consumers.

The National Restaurant Association, a leading member of the Merchants Payments Coalition, expressed disappointment with the final rule. "The Federal Reserve appears to have caved to lobbying by the big banks and debit-card companies and ignored the spirit of last year's Durbin Amendment, which was aimed at fixing a broken U.S. debit-fee market and bringing fairness to merchants and consumers who have no control over rising swipe fees," said Scott DeFife, NRA's executive vice-president of policy and government affairs.

"While the Fed's rule acknowledges that the card companies' practices have resulted in a broken market, and while the new cap will ensure that card companies cannot continue to arbitrarily increase debit interchange rates, this rule will not provide businesses and consumers with the savings they deserve under the law," he predicted.

The Durbin Amendment allows businesses to set a $10 minimum for credit-card payments and to offer discounts for a favored payment method (although they cannot favor payments made with cards from one issuer).

It also prevents card issuers from requiring merchants to use a specific transaction-processing network, thus increasing competition with the intent of lowering costs.